Anti-diabetic drug metformin has been shown to enhance osteoblasts differentiation and inhibit osteoclast differentiation in vitro and prevent bone loss in ovariectomized (OVX) rats. But the mechanisms through which metformin regulates osteoclastogensis are not known. Osteoprotegerin (OPG) and receptor activator of nuclear factor κB ligand (RANKL) are cytokines predominantly secreted by osteoblasts and play critical roles in the differentiation and function of osteoclasts. In this study, we demonstrated that metformin dose-dependently stimulated OPG and reduced RANKL mRNA and protein expression in mouse calvarial osteoblasts and osteoblastic cell line MC3T3-E1. Inhibition of AMP-activated protein kinase (AMPK) and CaM kinase kinase (CaMKK), two targets of metformin, suppressed endogenous and metformin-induced OPG secretion in osteoblasts. Moreover, supernatant of osteoblasts treated with metformin reduced formation of tartrate resistant acid phosphatase (TRAP)-positive multi-nucleated cells in Raw264.7 cells. Most importantly, metformin significantly increased total body bone mineral density, prevented bone loss and decreased TRAP-positive cells in OVX rats proximal tibiae, accompanied with an increase of OPG and decrease of RANKL expression. These in vivo and in vitro studies suggest that metformin reduces RANKL and stimulates OPG expression in osteoblasts, further inhibits osteoclast differentiation and prevents bone loss in OVX rats.

5-lipoxygenase (5-LOX), a member of the lipoxygenase gene family, is a key enzyme assisting in the conversion of arachidonic acid to 5-HETE and leukotrienes. Tumor-associated macrophages (TAMs) have a critical role in the progression and metastasis of many tumors, including ovarian tumors. Moreover, TAMs are often found in a high density in the hypoxic areas of tumors. However, the relevant mechanisms have not been studied explicitly until now. In this study, we found that the expression of 5-LOX strongly correlated with the density of TAMs in hypoxic areas of human ovarian tumor tissues. In cultured ovarian cancer cells, 5-LOX metabolites were increased under hypoxic conditons. Increased 5-LOX metabolites from hypoxic ovarian cancer cells promoted migration and invasion of macrophages, which was further demonstrated to be mediated by the upregulation of matrix metalloproteinase (MMP)-7 expression through the p38 pathway. Besides, we also showed that 5-LOX metabolites enhanced the release of tumor necrosis factor (TNF-α) and heparin-binding epidermal growth factor-like growth factor through upregulation of MMP-7. Furthermore, in animal models, Zileuton (a selective and specific 5-LOX inhibitor) reduced the MMP-7 expression and the number of macrophages infiltrating in the xenograft. Our findings suggest for the first time that increased metabolites of 5-LOX from hypoxic ovarian cancer cells promote TAM infiltration. These results of this study have immediate translational implications for the therapeutic exploitation of TAMs.

MiR-182 was up-regulated in colorectal cancer tissues and correlated with adverse clinical characteristics and poor prognosis, indicating that miR-182 might be involved in colorectal cancer progression and could be used as a potential prognostic biomarker and therapeutic target in the management of colorectal cancer.

Background/Aims: In the current study, we performed an integrated analysis of genome-wide methylation and gene expression data to find novel prognostic genes for lower-grade gliomas (LGGs). Methods: First, TCGA methylation data were used to identify prognostic genes associated with promoter methylation. Second, candidate genes that were stably regulated by promoter methylation were explored. Third, Cox proportional hazards regression analysis was used to generate a prognostic signature, and the signature genes were used to construct a survival risk score system. Results: Three genes (EMP3, GSX2 and EMILIN3) were selected as signature genes. These three signature genes were used to construct a survival risk score system. The high-risk group exhibited significantly worse overall survival (OS) and relapse-free survival (RFS) as compared to the low-risk group in the TCGA dataset. The association of the three-gene prognostic signature with patient’ survival was then validated using the CGGA dataset. Moreover, Kaplan-Meier plots showed that the three-gene prognostic signature risk remarkably stratified grade II and grade III patients in terms of both OS and RFS in the TCGA cohort. There was also a significant difference between the low- and high-risk groups in IDH wild-type glioma patients, indicating that the three-gene signature may be able to help in predicting prognosis for patients with IDH wild-type gliomas. Conclusion: We identified and validated a three-gene (EMP3, GSX2 and EMILIN3) prognostic signature in LGGs by integrating multidimensional genomic data from the TCGA and CGGA datasets, which may help in fine-tuning the current histology-based tumors classification system and providing better stratification for future clinical trials.